A glycoprotein (E-fraction) was extracted from the mucosa of the third stomach of a finback whale (Balaenoptera pysalus L.). E-fraction was isolated successively by extraction with water, precipitation with benzoic acid, fractionation with ammonium sulfate, and trypsin digestion. The E-fraction thus obtained contains protein or polypeptide, hexose, hexosamine, and sulfate, but no lipids or phosphorus. The glycoprotein fraction showed an inhibitory effect on gastric acid output of the Shay rat and in the Heidenhain pouch dog, and an increase of mucus secretion in the Heidenhain pouch dog. It was also found that the E-fraction had an obvious antagonistic effect on the action of synthetic gastrin-like polypeptide (tetragastrin) in the Schild's rat.
